In the past, various types of speed sensing devices, such as, electrical, electromagnetic and optical signal generators have been employed to measure the velocity of different ground vehicles, for example, automobiles, buses, transit cars and railroad trains. Generally, these previous types of signal generators included a rotor coupled to the vehicle axle which moved past a stator to produce signals which are directly proportional to the velocity or speed of the moving vehicle. It will be appreciated that while these conventional speed sensing devices have operated satisfactorily to varying degrees, there are certain aspects which must be carefully considered and effectively dealt with in order to maximize the velocity measuring operation. An acceptable speed measuring device must be capable of withstanding extreme shock and vibrations which are ever present in a roadway vehicular milieu. The violent and irregular agitation has a detrimental effect on any speed signal generator which utilizes frangible or unstable elements. Such previous apparatus is susceptible to breakage and misalignment of parts which either totally destroys or markedly reduces the signal generating ability of the speed sensing device. It is generally desirable to insure that a vehicle carried speed sensing generator includes inbuilt impedance matching and amplifying characteristics to minimize losses and to enhance the quality of the speed indicating signals. In addition, it is highly advantageous to provide a distinct type of positive signal when the vehicle is not moving or stopped and also when a failure has occurred in the speed sensing device.